1. Technical Field
The present invention relates to an optical device and a projector.
2. Related Art
There is known a projector including an optical modulator that modulates a luminous flux from a light source in response to image information and a projection optical device that magnifies and projects the luminous flux modulated by the optical modulator.
The optical modulator adopts, for example, an active matrix drive type liquid crystal panel having a liquid crystal hermetically sealed between a pair of substrates. Generally, an incidence side polarizing plate and emergence side polarizing plate which transmit a luminous flux having a predetermined optical axis are disposed on the luminous flux incidence side and luminous flux emergence side of the liquid crystal panel, respectively.
In the projector including the aforesaid liquid crystal panel, when a luminous flux is emitted from the light source, the liquid crystal panel is liable to a rise in temperature, and heat tends to occur even in the polarizing plates, because of light absorption by a liquid crystal layer, a black matrix, various interconnections, and the like.
There is the technique in which a transmissive cooling chamber serving as a liquid refrigerant layer is disposed between the liquid crystal panel and each of the polarizing plates, and in which a rise in temperature of the optical modulator and polarizing plate is suppressed by allowing a cooling fluid to flow through the cooling chamber (e.g., see JP-A-1-159684).
In the technique of allowing the cooling fluid between the liquid crystal panel and each of the polarizing plates, an image forming luminous flux passes through the cooling fluid. Therefore, the images of air bubbles, dust particles, or the like in the cooling fluid are included in an optical image formed on the liquid crystal panel, or the optical image fluctuates with a temperature distribution in the cooling fluid, which is likely to cause a deterioration in image quality. Besides, for example, when the cooling fluid is deteriorated, the transmittivity of the luminous flux is lowered to, as a result, reduce the illuminance and color reproducibility of the optical image on the liquid crystal panel.